FIG. 1 illustrates a light guide plate 9 of a light emitting keyboard, as disclosed by the applicant in Taiwanese Patent No. M525536. The light guide plate 9 is composed of a plurality of light guide blocks 91, each of which has a plurality of spaced-apart light blocking spaces 912 dividing the light guide block 91 into a plurality of light guide portions 911, and a plurality of light source receiving spaces 913 corresponding to the light guide portions 911 and respectively receiving the light sources (not shown). The light guide portions 911 correspond to the keys (not shown) of the light emitting keyboard. The light blocking spaces 912 are used to restrict light emitted from each light source to transmit within a respective one of the light guide portions 911. Through this, the luminance of each light guide portion 911 is controlled by a single light source, and is not affected by the other light sources. Hence, the luminance of the light guide portions 911 is uniform and approaches the luminance of each light source, and the luminance of light transmissive portions of the keys is also uniform.
However, since the light blocking spaces 912 can only prevent light emitted from each light source to transmit to a neighboring light guide portion 911, light emitted from the light sources in each light guide block 91 can still leak through a peripheral side thereof, so that the brightness of light emitted by each light guide portion 911 to the corresponding key is weakened, thereby reducing the light utilization efficiency of each light source. Further, although an outer frame (not shown) can be used to interconnect six rows of the light guide blocks 91 of the light guide plate 9, clearances among the light guide blocks 91 still exist. Moreover, each light guide block 91 has the light blocking spaces 912, so that the structural strength of the entire light guide plate 9 is weak, that is, each light guide block 91 is easily bent by an external force that causes the entire light guide plate 9 to warp, thereby adversely affecting the degree of closeness of the light guide plate 9 with the other components of the light emitting keyboard during assembly. Hence, there is still room for improvement of the light guide plate 9.